1. Field of the Invention
The present invention relates to wipers for industrial and other applications involving the absorption of water and/or oily materials. The many uses for such wipers include auto repair cleanup, lithographic plate processing, hand wiping, and many others. For such uses it is desirable to have a single material that wipes well for both oil and water residues. Further, since wiping is, in many cases, a hand labor step, it is also desired to obtain a wiper that wipes clean with a minimum effort, preferably on the first application. Finally, cloth wipers, which are most prevalent in industrial applications today, must be reused for economy and, as a result, are subject to pilferage and laundry costs. It is, therefore, desirable to obtain an improved wiper at a cost consistent with single use and disposability.
2. Description of the Prior Art
Many forms of wipers are available for various applications. In general, however, prior wipers can be classified as either paper or cloth. The paper wipers, while inexpensive, are suited primarily for use in wiping aqueous materials and not entirely satisfactory for use with oil. On the other hand, cloth wipers, while suitable for wiping both oils and water, are expensive and must be laundered. In addition, unless care is taken in laundering, water absorption rates for cloth wipers can be adversely affected. Some nonwoven wipers made from rayon which may also include other ingredients such as pulp, for example, and other synthetic materials have been available, but, in general, fail to provide good wiping properties with both oil and water and may entail a cost that prevents disposability except in special applications. Finally, sponges, both natural and synthetic, are in widespread use for wiping but are even more expensive.
Examples of prior wipers within these broad classifications are contained in the following U.S. patents which are intended to be representative and not exhaustive: U.S. Pat. No. 3,477,084 to Thomas, U.S. Pat. No. 3,520,016 to Meitner, U.S. Pat. No. 3,546,056 to Thomas, U.S. Pat. No. 3,650,882 to Thomas, and U.S. Pat. No. Re. 27,820 to Politzer et al.
The preparation of polyolefin microfiber webs is also known and described in Wente, Industrial and Engineering Chemistry, Volume 48, Number 8 (1965) pages 1342 through 1346 as well as U.S. Pat. No. 3,978,185 to Buntin et al, U.S. Pat. No. 3,795,571 to Prentice and U.S. Pat. No. 3,811,957 to Buntin. The Buntin et al patent further discloses that mats of meltblown polyolefins are useful as wiping cloths and hydrocarbon absorption material. However, the wipers as described in these publications each are deficient to a significant degree in one or more of the following properties: cost, combined oil and water wiping, clean wiping, or physical properties.